To efficiently wash lignoellulose raw material subjected to a chemical treatment and thus provide a raw material suited for saccharification.

Lignoellulose raw material is chemically treated to make it into a raw material suited for saccharification, and the raw material (raw material suspension) chemically treated is supplied with washing water by a washing drainer and is simultaneously dehydrated to remove impurities clinging to the raw material. The raw material washed is subjected to a solid-liquid separation by a solid-liquid separation device to separate the raw material into solid (raw material) and liquid. The raw material separated is subjected to an enzyme saccharification treatment in an enzyme saccharification treatment process. Ethanol is produced by using a fermentation micro-organism in the enzyme saccharification treatment process, and performing both a process that causes an enzyme saccharification reaction of the lignocellulose raw material and a fermentation process for produced saccharides using the fermentation micro-organism.